engleski

Hematological values in fallow deer (Dama dama L.) from Brijuni Islands in Croatia

Brijuni Islands comprise of 14 islands cowering the area of 734 ha. The islands are situated in the north Adriatic Sea, in front of the western Istrian coast. Brijuni are in the Mediterranean climate zone with the average year air temperature of 14&ordm ; ; C and plenty of humidity which enable the rich vegetation growth of underbush, holm oak, laurel and wide grasslands of 124 ha. Since 1900, the autochthonous animals and plants were endangered by imported alochthonous game animals: fallow deer, axis deer, mouflons and hares. These animals live without any fear of predators and they are not exposed to any mayor anthropogenic stress. The favourable living conditions have facilitate enhanced reproductive ability of fallow deer, but in the same time the food resources are insufficient for these large number of animals (16 animals per ha). Besides, in the National Park Brijuni no alteration in plant cover is permitted, and as a consequence, all vegetation available to deer (except poisonous plants like oleander and various species of cactus) is shaped by their grazing. Supplemental food, mainly corn, is constantly given to animals and inappropriate foodstuff is often offered by careless tourists. The comparative study of fallow deer from the Brijuni Islands and from the continental hunting grounds of Croatia documented numerous differences in biochemical values between animals (Poljičak-Milas et al., 2004). The results of conducted study indicate that besides age, sex and sampling methods, nutritional and environmental factors should be considered when evaluating serum biochemical parameters of fallow deer. The present study is resumption of research aimed to determine the physiological ranges of hematological parameters in the blood of fallow deer from Brijuni National Park. The study was conducted on 45 free ranging fallow deer from Brijuni National Park in Croatia between March and April, 2004. Blood samples were obtained from shot animals which were neither chased nor excited in other ways prior killing. In order to reduce the variation associated with diurnal rhythms, blood samples were taken at the same time in the morning, between 10 and 12. Blood for hematological analyses was taken immediately after killing from the jugular vein into vacuum tube with K3-EDTA (BD Vacutainer Systems, Playmounth, UK). Blood samples were stored and transported at +4&ordm ; ; C until analysed, 10 h after withdrawal. Hematological parameters, total white blood cell count (WBC), red blood cells count (RBC), hemoglobin concentration (Hb), packed cell volume (PCV), as well as calculated red blood cell parameters, mean cell hemoglobin (MCH), mean cell volume (MCV), mean cell hemoglobin concentration (MCHC) and red cell distribution width (RDW) were determined using hematological counter SERONO - 9120 Baker System. White blood cell differentiation was performed microscopically on blood smears stained with May-Grünwald-Giemsa method. The animals in the research were divided in four groups regarding the gender and age. The juvenile groups consist of animals up to 18 month (9-11), and adult groups, animals older than 18 months (2-8 year). The distribution of each variable was tested by Shapiro-Wilks' W test. Mean values, standard deviations and 95% confidence limits for mean values of each parameter and comparisons of mean values were done with STATISTICA 6.1 software (StatSoft Inc. 2003 USA). Judgement of basic physiological ranges and variability in individual species is important to provide reference data for diagnosis of disease and for the monitoring of health status. Moreover, game animals can serve as an environmental quality bioindicator. The results of comparative hematological parameters between the particular groups of animals are presented in the table 1. The comparison of hematological parameters regarding the gender showed no significant differences between juvenile male and female animals. Regarding the red blood cell indices, in the elderly animal groups, males had significantly higher MCH than females (Table 1.). Although, the average values of RBC, Hb and PCV in our study agree with the results of Kováč et al. (1997) research, conducted on similar groups of fallow deer, the significantly higher Hb and PCV was demonstrated in referred research. In our study, the adult females had significantly higher PCV, MCV, but lower MCHC than juvenile females. On the other hand, there were no significant differences in red blood indices between the adult and juvenile male animals. Even though the average Hb and PCV values in juvenile male animals were lower than in adult males, wide individual variability in juvenile group was the possible reason why these differences was not statistically confirmed. Specifically, in the juvenile female group, two fawns had rather low RBC, Hb and PCV, whereas in the juvenile male group, in one fawn exceptionally low RBC and Hb were observed. Zomborszky et al. (1997) found the similar variations of red blood cell indices in six-month-old fallow deer. It is presumed that the blood composition of deer game (white tailed deer, mule deer and roe deer) reaches adult values by about 6 moths of age (Chapman, 1977). The differences in red blood cell indices between the age groups of deer in our study may have been also an impact of physiological blood differences between the adult and juvenile animals, since the RBC, Hb and PCV values were the lowest in the youngest animals in groups. To exclude anemia, it would be of great importance to evaluate the serum iron concentration as well as percent of transferrin saturation. Also, the available food should be analysed. The mycrocites, which are generally commonly seen in young animals of most species, as well as in our research, may be also observed in iron deficiency and pyridoxine deficiency anemia. In our research the RBC and Hb values in blood of adult animals were lower than in the research of physically restrained fallow deer (Zomborszky at al., 1997), and trapped and thereafter transported female fallow deer (English and Lepherd, 1981). The higher RBC count and Hb concentration in stated studies were related to excitement and a consequent blood release from the spleen. In the judgment of the results, nutritional and management differences should not be omitted. There was no difference in the total WBC count between investigated groups of deer, and this supports the published data for a number of species of deer, in which there were no marked species, sex or age differences in the WBC count (Chapman, 1977). Regarding the white blood cell differentiation, the significantly higher eosinophile count was detected in adult males comparing to juvenile males, which was possibly result of the higher exposure of adult animals to endoparasitic invasion. The average WBC count in all animal groups ranged over the similar, rather low values (3.77-4.27 x 109/L) with lymphocytes as predominant white cells. Several researches on fallow deer presented different total and differential WBC count (Peinado et al., 1999 ; Zomborszky et al., 1997 ; Kováč et al., 1997), probably because of stress during the immobilisation and manipulation of animals, as well as anesthetic administration. In addition, nutrition, stage of gestation and disease are further possible environmental and physiological factors that should be taken into the consideration while evaluating results.

red blood cells indices; total leukocyte count; differential leukocyte count

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